Leuco-compounds of vat dyes



Patented Apr. 10, 1934 UNITED STATES PATENT OFFICE LEUOO-COMPOUNDS 0F VAT DYES No Drawing. Application August 19, 1927, Serial No. 214,217

33 Claims.

This invention relates to organic salts of the acidic derivatives of the leuco-compounds of vat colors and more especially to the alkylolamine salts, for example, those produced by the interaction of these acidic bodies and diand triethanolamine or mixtures of these.

The stabilizing of the leuco-compounds of vat colors has been an object of other inventions because of its importance to the dyeing industry. Methods for producing stable acidic derivatives of the leuco-compounds of vat colors have been patented as described in British Patents Nos. 248302-245,587-247,?8'7-251,491. These four British patents disclose the treatment of vat dyes of every class, such as, broadly, the indigo, thioindigo, anthraquinone, benzanthrone and indanthrone vat dyes, and specifically indigo, flavanthrone, indanthrone, anthraquinone-2:l-naphthacridone, di methoxy dibenzanthrone, dichloro-isodibenzanthrone, pyranthrone, nitrodibenzanthrcne, dichlorindanthrone, and the various indigoids and halogenated indigos, such as 4 4' -dichlor-'7 7 -dibrom-indigo, 5 5-dibrom- 6 2 6-diethoxy-thioindigo, 5 5-7 7 -tetrabromindigo, and, in fact, any vat dye. The leuco form of these vat dyes reacts to form esters with acidic compounds, and preferably polybasic acid compounds such as alkyl sulphuric acid halides, phosphorus oxy-chloride, alkyl phosphoric dichlorides, chlorsulphonic acid, sulphuric anhydride, fuming sulphuric acid, and salts of pyro-sulphuric acid. It is with such esters of leuco vat dyes that my invention is concerned.

These acidic compounds and others derived from the leuco-compounds by the action of the chlorides of phosphorus and of chlor-acetic acid are water soluble by reason of the fact that they form sodium and potassium salts. When submitted to oxidation they revert to the vat color in its insoluble form. The vat colors of the present invention contain a ketone group. This ketone group on reduction with hydrosulfite and caustic is converted into the group This, in turn, in the presence of the caustic soda, forms the sodium salt which is soluble and acts as the dye. It will be apparent that if this sodium salt could be stabilized, it would be unnecessary to perform the reduction every time the step of dyeing is carried out, and moreover, it could be used in the absence of alkali.

However, this leuco compound containing the grouping is so extremely unstable that it oxidizes instantly when the reducing agent is removed, giving rise to the original vat color. If the leuco compound containing the grouping is made and freed from reducing agent in the absence of air and in the presence of an organic base such as pyridine or dimethylaniline, it is possible to remove all the water necessary for the reduction without oxidizing the compound. When the water-free mixture of the sodium salt of the leuco compound and chlorosulfonic acid are brought together the sulfonic acid group takes the place of the sodium, resulting in a reaction most probably represented by the following general equation:

I have found that when an organic base containing hydroxyl groups and represented by the general formula given below is substituted for the sodium in the acidic esters of the leucocompounds referred to above, the resulting product has distinct advantages because of the surprising fact that these esters are much more soluble and dissolve better than the alkali salts. In fact, by their use one can overcome the great objection to the acidic derivatives at present in commerce that they do not keep well and show an increasing insolubility. For this purpose, it is possible to use bases of the following general type:

Air-0H N-Rr \R:

where Alk represents an aliphatic or hydroxy aliphatic radical, R1 and R2 represent hydrogen or an aliphatic radical or a hydroxy aliphatic radical or a poly-hydroxy aliphatic radical.

The sodium salts of the sulfuric acid esters of vat leuco-compounds in the form of pastes are commercial dyestuffs known in the trade under a more soluble product.

the name of Indigosol or Soledon colors. These esters have the disadvantage, however, of not being very stable and not being as soluble as may be desired in dyes of this kind.

In making my new soluble forms I may proceed as follows:

The sodium salt of the sulfuric acid ester of the vat leuco-compound in the form of a paste is treated with a suitable organic acid. This resuits in the precipitation of the free sulfuric ester of the vat leuco-compound. This acid is separated and then dissolved by the addition of a mixture of diand triethanolamine. The following procedure may be used in carrying out my invention, but it is to be understood that this is illustrative only and is not to be taken as a limitation of my invention. v v

One thousand parts of the dye known as Soledon jade green paste are poured into a beaker and 1000 parts of water are added. To the resulting liquid a 20% acetic acid solution is added slowly, with stirring, until the reaction becomes acid, the temperature being maintained between 20 C. and 25 C. The free leuco sulfuric acid ester precipitates. It is then filtered off quickly, and rinsed with a little water until the filtrate is neutral. The filter cake is pressed as far as possible to free it from moisture. To 250 parts of the filter cake are added 250 parts of diethanolamine.

It may be stated that the addition of acetic acid gives a leuco-sulfuric ester because an equilibrium is set up, the free sulfuric ester being formed. This may be represented by the following general equation:

The dye dissolves and the concentration of the thick pasty material is twice that of the original dye. It is preferable to conduct the operation in the absence of oxygen, but this is not absolutely necessary.

The quantity of ethanolamine used may be varied, as also the quantity of water in the prodnot, without altering the condition. Monoethanolamine or tri-ethanolamine or methyl-dipropane-diol-amine may be substituted in the example given, and similar results obtained. Instead of the dye mentioned any of the soluble acidic derivatives may be used.

Instead of preparing the organic salt in this way, a similar result may be obtained by adding the organic base to a printing paste in which the soluble acidic derivative of the leuco-vat color is used. For instance, a printing paste made with 100 parts of the commercial soluble acidic derivative of any or" the vat leuco-compounds mixed with parts of one of the bases mentioned above and 820 parts of British gum starch thickening may be printed in the ordinary way either on cotton, silk or wool. After printing, the goods are aged from four to five minutes in the usual manner, passed into an oxidizing bath containing either ferric chloride or sodium nitrite and sulfuric acid or ammonium persulfate.

It is not necessary to isolate the free acid derivative of the vat color leuco-compound to obtain The direct addition of the organic bases described to the commercial dyes apparently causes a formation of compounds of higher solubility, or acts merely as a solvent. In any event, the solution is rendered much better and the tendency to precipitate is lessened very greatly.

As many apparently widely different variations of this invention may be made without departing from the spirit thereof, it is to be understood that I do not limit myself to the foregoing examples or description except as indicated in the following patent claims.

I claim:

1. The process of producing alkylolamine salts of inorganic sulphur and phosphorus acidic esters of leuco-vat dyes, which comprises combining the acidic ester with an alkylolamine.

2. The process of producing alkylolamine salts of inorganic sulphur and phosphorus acidic esters of leuco-vat dyes, which comprises combining the acidic ester with an ethanolamine.

3. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises combining the acidic ester with an alkylolamine.

4. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises combining the acidic ester with an ethanolamine.

5. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises combining the acidic ester with triethanolamine.

6. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises treating an alkali metal salt of the said ester with an organic acid and thereafter treating the mixture with an alkylolamine.

7. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises treating a sodium salt of the said ester with acetic acid and thereafter treating the mixture with an alkylolamine.

8. The process of producing alkylolamine salts of inorganic sulphur and phosphorus polybasicacid esters of leuco-vat dyes, which comprises treating a sodium salt of the said ester with acetic acid and thereafter treating the mixture with a mixture of diand triethanolamines.

9. The process of producing an alkylolamine salt of a sulphuric acid ester of a leuco-vat dye, which comprises combining the ester with an alkylolamine.

10. The process of producing an alkylolamine salt of a sulphuric acid ester of a leuco-vat dye,

which comprises combining the ester with an ethanolamine.

11. The process of producing an alkylolamine salt of a sulphuric acid ester of a leucovat dye, which comprises combining the ester with a mixture of diand triethanolamine.

12. The process of producing an alkylolamine salt of a sulphuric acid ester of a leuco-vat dye, which comprises treating the sodium salt of the said ester with acetic acid and thereafter treating the mixture with an alkylolamine.

13. The process of producing an alkylolamine salt of a sulphuric acid ester of a leuco-vat dye, which comprises treating the sodium salt of the said ester with acetic acid and thereafter treating the mixture with an ethanolamine.

14. The process of producing an alkylolamine salt of a sulphuric acid ester of a leuco-vat dye, which comprises treating the sodium salt of the said ester with acetic acid and thereafter treating the mixture with a mixture of diand triethanolamines.

15. As new products, the alkylolamine salts of inorganic sulphur and phosphorus acidic esters of leuco-vat dyes.

16. As new products, the ethanolamine salts of inorganic sulphur and phosphorus acidic esters of leuco-vat dyes.

17. As new products, a mixture of diand triethanolamine salts of inorganic sulphur and phosphorus acidic esters of leuco-vat dyes.

18. As new products, the alkylolamine salts of inorganic sulphur and phosphorus polybasic-acid esters of leuco-vat dyes.

19. As new products, the ethanolamine salts of inorganic sulphur and phosphorus polybasic-acid esters of leuco-vat dyes.

20. As new products, a mixture of diand triethanolamine salts of inorganic sulphur and phosphorus polybasic-acid esters of leuco-vat dyes.

21. As new products, the alkylolamine salts of sulphuric acid esters or" leuco-vat dyes.

22. As new products, the ethanolamine salts of sulphuric acid esters of leuco-vat dyes.

23. As new products, a mixture of diand triethanolamine salts of sulphuric acid esters of leuco-vat dyes.

24. The process of producing alkylolamine salts of acidic esters of leuco vat colors which comprises combining an alkylolamine with an acidic ester of a leuco vat color selected from the group consisting of inorganic sulphur and phosphorous acidic esters of the indigo, thioindigo, anthraquinone, benzanthrone and indanthrone series.

25. The process of producing alkylolamine salts of acidic esters of leuco vat colors which comprises combining an alkylolamine with an ester resulting from the esterification of a leuco vat color with an acidic compound selected from the group consisting of alkyl-sulphuric acid halides, phosphorus-oxy-chloride, alkyl-phosphoric di-chlorides, chlor-sulphonic acid, sulphuric-anhydride, fuming-sulphuric acid, salts of pyro-sulphuric acid and chlor-acetic acid.

26. The products obtained by combining an alkylolamine with an acidic ester resulting from the esterification of a leuco vat color selected from the group consisting of indigo, thio-indigo, anthraquinone, benzanthrone and indanthrone vat colors with an esterifying agent selected from the group consisting of alkyl-sulphuric acid halides, phosphorus-oxy-chloride, alkyl-phosphoricdi-chlorides, chlor-sulphonic acid, sulphuric-anhydride, fuming-sulphuric acid, salts of pyrosulphuric acid and chlor-acetic acid.

27. The products which are alkylolamine salts of sulphuric acid esters of the indigo, thio-indigo, benzanthrone and indanthrone series.

28. The products which are ethanolamine salts of sulphuric acid esters of the indigo, thicindigo, anthraquinone, benzanthrone and indanthrone series.

29. The products which are alkylolamine salts of a sulphuric acid ester of a leuco vat color of the anthraquinone series.

30. The products which are alkylolamine salts of a sulphuric acid ester of a leuco vat color of the benzanthrone series.

31. The products which are ethanolamine salts of a sulphuric acid ester of leuco di-methoxy-dibenzanthrone.

32. The process of producing alkylolamine salts of acidic esters of leuco vat colors which comprises combining an alkylolamine with an acidic ester resulting from esterifying a leuco vat color with an esterifying agent selected from the group consisting of alkyl sulfuric acid halides, alkyl phosphoric acid halides, chlor-acetic acid and inorganic sulfur and phosphorus esterifying agents.

33. The products obtainable by combining an alkylolamine with an acidic ester resulting from the esterification of a leuco vat color with an esterifying agent selected from the group consisting of alkyl sulfuric acid halides, alkyl phosphoric acid halides, chlor-acetic acid and inorganic sulfur and phosphorus esterifying agents.

JEAN GEORGES KERN. 

